1. Field of the Invention
Embodiments of the invention generally relate to the field of electrical wiring devices that include a circuit protection component such as a ground fault circuit interrupter (GFCI). More particularly, embodiments of the invention are directed to an electrical wiring device that includes a circuit protection component having an optical/visual circuit status or condition indicator, which is physically, visually, ergonomically or otherwise informatively associated with a circuit RESET or TEST activator component of the device.
2. Description of Related Art
Ground fault circuit interrupter (GFCI) devices are designed to trip in response to the detection of a ground fault condition in a load circuit. Generally, the ground fault condition results when a person comes into contact with a line (or hot) conductor in the load circuit and an earth ground at the same time. This situation can result in serious injury. The GFCI device detects this type of condition by using a sensing transformer to detect an imbalance between the currents flowing in the line and neutral conductors of the AC supply, as will occur when some of the current to the load circuit is being diverted to ground. When such an imbalance is detected, a circuit breaker within the GFCI device is tripped to an open condition, thereby opening at least the line conductor to the load and removing power from the ground fault.
GFCIs are just one member of a family of protective devices that also includes arc fault circuit interrupters (AFCIs) and units that include both AFCI and GFCI protection. An AFCI is designed to detect an electrical arcing condition that if allowed to persist could ignite nearby combustibles. Arcs may occur in a loose electrical connection intended to carry current to a load, or between two electrical conductors that are not isolated electrically from each other. An arc fault condition typically manifests itself as a high frequency current signal. Accordingly, an AFCI may be configured to detect various high frequency signals and trip a circuit breaker. As a result of the tripping, the load circuit along with the arc fault current is interrupted before combustibles in proximity to the arcing fault have a chance to ignite. Whereas the principles of the invention are described in concert with GFCI devices, it is to be understood that they are applicable to other protective devices such as those set forth herein by way of example.
GFCI devices come in various forms, including portable or line cord devices and central units that provide protection for a portion of the AC wiring throughout a structure. Central units are, by way of example, GFCI circuit breakers incorporated in an electrical distribution panel and GFCI receptacles incorporated into wall-mounted AC electrical receptacles that are designed for installation at various locations within a building. A typical receptacle configuration consists of a housing adapted to be received within a standard electrical box, with a pair of standard two- or three-prong AC outlets, a ‘TEST’ pushbutton and a ‘RESET’ pushbutton accessible through the front of the housing. At the rear of the housing, two pairs of screw terminals are ordinarily provided. One pair of screw terminals, which are sometimes referred to as source or line terminals, allow the line and neutral conductors from an AC source to be connected to the GFCI receptacle, and these terminals are connected to the electrical outlets at the front of the housing via the GFCI circuitry and circuit interrupter within the housing. The second pair of screw terminals, which are sometimes referred to as load or feed-through terminals, are connected directly in parallel with the contacts of the AC outlets. This provides the installer with the option of connecting a standard, non-GFCI AC receptacle to the GFCI receptacle. The GFCI receptacle provides ground fault protection to the standard receptacle's outlets without the need to provide a separate GFCI circuit. The standard receptacle may be located remotely from the GFCI receptacle, but will ordinarily be close enough (e.g., in the same room) so that convenient resetting is possible when a ground fault condition occurs.
The TEST pushbutton referred to above allows a user to manually initiate a simulated fault condition to test the operating condition of the GFCI. Actuation of the TEST pushbutton results in removal of power from the load circuit which is typically indicated on the device by the popping out of the RESET pushbutton. To restore power to the load circuit, the user actuates the RESET pushbutton.
Unfortunately, there is a problem with GFCI receptacles of the type described above, in that the installer may erroneously connect the incoming AC source conductors to the load or feed-through terminals of the receptacle rather than to the source or line terminals. Because of the nature of the internal wiring of a GFCI receptacle, this miswiring condition is not easily detected. AC power can still be present at the receptacle outlets, making it appear that the GFCI receptacle is operating normally and providing the desired ground fault protection. If the TEST pushbutton is depressed, the circuit breaker within the GFCI receptacle will be released and the RESET pushbutton will pop out, again making it appear that the GFCI receptacle is operating normally and providing the desired ground fault protection. In reality, however, no such protection is being provided because the AC source has been wired directly to the receptacle outlets without passing through the internal circuit breaker of the GFCI device.
It is known to provide a GFCI receptacle with a visual indicator, such as a light-emitting diode (LED), to indicate that the GFCI has been properly wired. If the receptacle has been wired properly, the LED is extinguished in response to activating the test button. However, in the event that the receptacle has been miswired by connecting the AC source to the load terminals rather than to the line terminals, the LED is not extinguished when a ground fault condition occurs. Thus, the LED remains illuminated to serve as an indication that the receptacle has been miswired. Unfortunately, however, the installer of the receptacle cannot necessarily be relied upon to understand the operation of the LED. That is, the failure of the LED to extinguish after the TEST button is depressed may not be interpreted by the installer as an abnormal condition, particularly since the installer will observe the popping out of the RESET button. Thus, the miswiring of the receptacle may not be detected and a dangerous condition may be allowed to persist.
Known GFCIs have included various types of visual indicators. Examples are trip indicators that illuminate when the circuit breaker has tripped, pilot indicators that illuminate when the circuit breaker is reset, and end-of-life indicators that illuminate when the GFCI is experiencing an internal fault condition and is no longer affording protection. Due to the plethora of indicators, the user may mistakenly believe that the particular indicator is for one purpose when in fact it is included in the GFCI for an entirely different purpose. As a result, visual indicators have led to confusion rather than to solution. This is particularly true in construction sites, hotel rooms, and other similar situations where someone may be confronted by an unfamiliar device model.
Known visual indicators have been somewhat effective for indicating a status of the load circuit. The trip indicator, for example, emits light to indicate that power is not available in the load circuit and even that the GFCI is responsible for the loss. Unfortunately these indicators do not guide the user in what to do next.
In another aspect, a GFCI is periodically tested by way of the TEST button and RESET button. A visual indicator, if provided, is typically in proximity to these buttons. Unfortunately given the variety of meanings of visual indicators, the indicator may cause confusion about how the test and reset buttons are to be manipulated and even whether or not the test passed. As a result of the testing process not being user friendly, some users have shied away from testing, thus a device no longer affording protection remains in service.
What is needed is a user-friendly visible indicator. In particular, what is needed is a visible indicator configured to lead the user to perform a pre-determined task in an intended manner.